/Engine/Source/Editor/LevelEditor/Public/SLevelViewport.h
a new custom column for a scene outliner that indicates whether each actor is locked to this viewport
[TSharedRef](API\Runtime\Core\Templates\TSharedRef)< class [ISceneOutlinerColumn](API\Editor\SceneOutliner\ISceneOutlinerColumn) > CreateActorLockSceneOutlinerColumn ( class [ISceneOutliner](API\Editor\SceneOutliner\ISceneOutliner) & SceneOutliner ) const